nx_rights_ledger_store.nx

nx_rights_ledger_store.nx -- RUNG 2: durability for the rights ledger. Persists the ledger through nx_seg_store (append-only, crash-safe temp-> rename commit) so a license SURVIVES a restart on the NAS. The snapshot value is the raw contiguous row buffer (the row count is derived from the value length, so no header is needed); each save is a NEW immutable segment -> ss_scan_all over "rights:snapshot" is the full audit history. HONEST scope: this is a whole-ledger snapshot under one key. Per-row content-addressed records (a canon_cid CID per license) + key-level history = rung 2b (flagged, NOT a silent cap). license_tier: ORIGINAL